Ion-conducting polymer binder for positive electrodes

Abstract

This invention provides an ion-conducting polymer binder for battery electrodes that possesses excellent mechanical properties and ion conductivity. [Solution] The present invention provides a repeating unit of m according to formula (I), and a repeating unit of n according to formula (II), TIFF2026057506000023.tif31170 TIFF2026057506000024.tif58170 Regarding an ion-conducting polymer binder for a positive electrode containing (CH2), R1 is (CH2) x -R3, x is 1-20, and R3 is H or CN; R2 and R5 are alkyl or alkenyl; M is alkali metal, etc.; m / n ratio is 25:1-1:25; m+n is q, q is 50-5000.

Description

[Technical Field]

[0001] This invention relates to an ion-conducting polymer binder for the positive electrode of a battery. Furthermore, this invention relates to a positive electrode containing the ion-conducting polymer binder, and a method for producing the ion-conducting polymer binder. [Background technology]

[0002] To realize high-energy-density batteries, the development of cathodes, particularly binders, is attracting significant attention in terms of both weight and capacity. Conventional binders used in cathodes, such as polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), and polyacrylic acid (PAA), possess the mechanical integrity required for high loads and repeated charge-discharge cycles. However, achieving good ionic conductivity with these binders depends heavily on the wettability of the electrolyte or the addition of metal salts or ionic liquids to the binder polymer, and this becomes a more difficult challenge as the cathode thickness increases.

[0003] For these reasons, the development of ion-conducting polymer binders is crucial. However, many known ion-conducting binders have a high degree of crystallinity, which negatively affects their properties, particularly mechanical properties, and impairs the mechanical integrity of the cathode. To address this problem and achieve mechanically stable, high-loading cathodes, polymer blends incorporating PVDF (photovoltaic fiberglass) are being employed.

[0004] Polysalts are a novel type of material attracting attention as ion-conducting polymer binders for the cathodes of batteries, particularly lithium-ion batteries. These materials are polymers containing ionic groups, which give the polymer intrinsic ionic conductivity. This intrinsic ionic conductivity can enhance ionic conductivity within the cathode and improve charge-discharge rates compared to conventional metal salt-added polymer binders. They also appear to be electrochemically stable over a wide voltage range, and the degradation of the binder over time is suppressed, especially in high-voltage cathodes. Polysalts have also demonstrated compatibility with high-energy cathode materials such as lithium nickel manganese cobalt oxide (NMC) and lithium nickel cobalt aluminum oxide (NCA), contributing to the achievement of high energy density without compromising cycle life.

[0005] Patent Document 1 discloses electrodes for lithium-ion batteries that include an inelastic binder. The binder may be a lithium polysalt of a carboxylic acid and a sulfonic acid, and includes lithium poly(meth)acrylate, lithium polystyrene sulfonate, and lithium polysulfonate fluoropolymer. These binders enable the suppression of irreversible capacity and performance degradation. Electrodes containing a lithium polysalt binder significantly reduce the irreversible first-cycle capacity loss of the electrode. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2008 / 097723 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to overcome one or more of the above-mentioned drawbacks. The object of the present invention is to provide an ion-conductive polymer binder for an electrode of a battery, particularly for a positive electrode, which has excellent mechanical properties and excellent ion conductivity and is very suitable for use with good rate characteristics even at high loadings. Another object is to provide an ion-conductive polymer binder having high thermal stability and heat resistance and / or excellent resistance to high voltages (i.e., high oxidation stability).

[0008] Yet another object is to provide an ion-conductive polymer binder that has high compatibility with commercially available active materials and excellent adhesion to them and to any conductive compound used in the electrode. Furthermore, it is also an object to provide an ion-conductive polymer binder that can produce a self-supporting and flexible electrode.

[0009] A further object is to provide an ion-conductive polymer binder whose adhesive strength and ion conductivity can be adjusted according to applications such as other components of the electrode and / or the composition and properties of the electrolyte.

[0010] Yet another object is to provide an ion-conductive binder that significantly reduces the amount of halogen atoms compared to polymer binders of the prior art and improves sustainability.

[0011] Another object of the present invention is to provide a method for manufacturing such an ion-conductive polymer binder for an electrode by a process that minimizes the use of harmful solvents or eliminates the need for such solvents, thereby reducing the environmental footprint.

[0012] Furthermore, it is an object to provide an electrode, particularly a positive electrode, having at least equivalent or better performance than an existing electrode containing a commercially known polymer binder. This performance includes mechanical properties, particularly adhesive strength, electrode-electrolyte interface resistance, ease of handling, and ease of assembly into a battery cell, as well as the electrochemical performance of a battery cell containing such an electrode. [Means for Solving the Problems]

[0013] A first aspect of the present invention discloses an ion-conductive polymer binder for a positive electrode described in the appended claims.

[0014] The ion-conductive polymer binder contains a repeating unit of m according to formula (I)

[0015] TIFF2026057506000002.tif33170

[0016] where R1 is (CH2) x -R3, x is 1 to 20, and R3 is H or CN; and R2 is C1-C 10 alkyl or C2-C 10 alkenyl.

[0017] The ion-conductive polymer binder further contains a repeating unit of n according to formula (II)

[0018] TIFF2026057506000003.tif58170

[0019] where R2 and R5 are each independently C1-C 10 alkyl or C2-C 10 alkenyl; M is an alkali metal or an alkaline earth metal.

[0020] That is, the ion-conductive polymer binder is a copolymer containing a repeating unit of m according to formula (I) and a repeating unit of n according to formula (II).

[0021] The ratio of m to n, that is, the ratio of the number of repeating units according to formula (I) to the number of repeating units according to formula (II) is 25:1 to 1:25, preferably 20:1 to 1:20, more preferably 10:1 to 1:10, most preferably 5:1 to 1:5, for example 4:1 to 1:4, 1:2 to 2:1, for example 1.4:1.

[0022] The total number of repeating units, m+n, or q, is 50 to 5000, preferably 75 to 4500, and more preferably 100 to 4000.

[0023] A first particularly preferred example of an ion-conducting polymer binder is one in which x is 6, R3 is CN, R2 is (CH2)2, and R5 is (CH2)2. A second particularly preferred example of an ion-conducting polymer binder is one in which x is 10, R3 is H, R2 is (CH2)2, and R5 is (CH2)2.

[0024] Advantageously, M is Li, Na, or Mg, preferably Li.

[0025] A second aspect of the present invention discloses a battery positive electrode as described in the appended claims. The positive electrode comprises an ion-conducting polymer binder according to the first aspect.

[0026] Advantageously, the positive electrode contains 75-95% by weight, preferably 80-95% by weight, more preferably 85-92% by weight, for example 90% by weight of the active material relative to the total weight of the positive electrode.

[0027] Advantageously, the positive electrode contains 1 to 15% by weight, preferably 2 to 12% by weight, and more preferably 5 to 10% by weight of the conductive compound relative to the total weight of the positive electrode.

[0028] Advantageously, the positive electrode comprises 1 to 15% by weight, preferably 2 to 12% by weight, and more preferably 5 to 10% by weight, of an ion-conducting polymer binder according to the first embodiment of the present invention, based on the total weight of the positive electrode.

[0029] Advantageously, the positive electrode comprises 75 to 95% by weight of an active material, 1 to 15% by weight of a conductive compound, and 1 to 15% by weight of an ion-conductive polymer binder according to a first aspect of the present invention, based on the total weight of the positive electrode.

[0030] Advantageously, the total weight percentage of the active material, the conductive compound, and the ion-conductive polymer binder of the present invention in the positive electrode is 100%, that is, the positive electrode advantageously consists of the active material, the conductive compound, and the ion-conductive polymer binder of the present invention. As understood by those skilled in the art, when the total of these three components reaches 100%, in order to reach 100%, the positive electrode contains a conductive compound of more than 1% by weight and a binder of the present invention of more than 1% by weight, for example, 75% by weight of the active material and 12.5% by weight each of the conductive compound and the binder of the present invention, or 90% by weight of the active material, 3% by weight of the conductive compound, and 7% by weight of the binder of the present invention.

[0031] Advantageously, the positive electrode has a porosity of at least 20%, preferably at least 25%, more preferably at least 30%, for example at least 40%. The porosity is expressed as the ratio of the density of the positive electrode to the theoretical density of the positive electrode. The theoretical density of the positive electrode is calculated from the composition of the positive electrode and the density of each compound in the positive electrode.

[0032] Advantageously, the active material includes one or more of lithium nickel cobalt manganese oxide (NMC), LiFePO4, and V2O5, or consists essentially of these. Preferred examples of NMC include LiNi 0.8 Mn 0.1 Co 0.1 O2 (NMC811) and LiNi 0.6 Mn 0.2 Co 0.2 O2 (NMC622).

[0033] Advantageously, the conductive compound contains carbon. The carbon can exist in forms well-known in the art such as carbon nanotubes or carbon black.

[0034] A non-limiting example of the positive electrode of the present invention is a positive electrode containing 85 - 95% by weight of NMC, 2 - 10% of a conductive compound containing carbon black, and 2 - 10% by weight of the ion-conductive polymer binder of the first aspect with respect to the total weight of the positive electrode.

[0035] Advantageously, the positive electrode consists of NMC, a carbon black-containing conductive compound, and the ion-conducting polymer binder of the present invention, i.e., the positive electrode contains no further components (additives), and the sum of the weight percent of these three components is advantageously 100%. A particularly preferred example of such a positive electrode is one consisting of 90 wt% NMC, 5 wt% carbon black-containing conductive compound, and 5 wt% of the ion-conducting polymer binder of the present invention.

[0036] A more non-limiting example of the positive electrode of the present invention is a positive electrode comprising 75-85% by weight of LiFePO4 (LFP), 5-15% of a carbon black-containing conductive compound, and 5-15% by weight of an ion-conductive polymer binder of the first embodiment, based on the total weight of the positive electrode.

[0037] Advantageously, the positive electrode consists of LFP, a carbon black-containing conductive compound, and the ion-conducting polymer binder of the present invention, i.e., the positive electrode contains no further components (additives), and the sum of the weight percent of these three components is advantageously 100%. A particularly preferred example of such a positive electrode is one consisting of 80 wt% LFP, 10 wt% carbon black-containing conductive compound, and 10 wt% of the ion-conducting polymer binder of the present invention.

[0038] A third aspect of the present invention discloses a method for producing an ion-conducting polymer binder as described in the appended claims. The ion-conducting polymer binder conforms to the first aspect of the present invention.

[0039] The method involves using an amino derivative according to H2N-R1, as shown in formula (III)

[0040] TIFF2026057506000004.tif27170

[0041] The process involves reacting a polymer containing repeating units of q according to the formula, where R1 is as described above, R2 is as described above, and q is 50 to 5000, preferably 75 to 4500, more preferably 100 to 4000.

[0042] The reaction is carried out in the presence of dimethylformamide (DMF).

[0043] The reaction is carried out at a temperature of 15-50°C, more preferably 15-30°C, for example, room temperature T1.

[0044] The reaction forms a first intermediate polymer. Advantageously, the first intermediate polymer has n repeating units according to formula (III) and formula (IV)

[0045] TIFF2026057506000005.tif33170

[0046] It contains repeating units of m according to the formula, and m+n is equal to q.

[0047] Next, the first intermediate polymer is F3CO2SN - O2S-R4-NH2M + The reaction is as described above, and R4 and M are as described above.

[0048] The reaction is carried out in the presence of DMF.

[0049] The reaction is carried out at a temperature of 15-50°C, more preferably 15-30°C, for example, room temperature T2.

[0050] The reaction forms a second intermediate polymer. Advantageously, the intermediate polymer does not contain ring closures, particularly imide rings, in its molecular structure. Advantageously, the second intermediate polymer has repeating units of m according to formula (IV) and formula (V)

[0051] TIFF2026057506000006.tif58170

[0052] It contains a repeating unit of n according to the formula, where m+n is equal to q.

[0053] Next, the imide ring-closing of the second intermediate polymer is performed, thereby forming an ion-conducting polymer binder. The imide ring-closing step can be carried out by heating the second intermediate polymer to a temperature T3, which is higher than T2, and then raising the temperature from T3 to T4 (i.e., further heating). Alternatively, the imide ring-closing step can be carried out at T2 in the presence of a catalyst. In other words, if a catalyst is used for imide ring-closing, it is not necessary to heat the second intermediate polymer.

[0054] Advantageously, the temperature T3 is 30 to 80°C, preferably 35 to 70°C, more preferably 40 to 60°C, for example 50°C.

[0055] Advantageously, the temperature T4 is 100 to 250°C, preferably 125 to 200°C, and more preferably 150 to 180°C.

[0056] Advantageously, when heating the second intermediate polymer to close the imide ring, this is done in the presence of DMF.

[0057] Advantageously, when the imide ring is closed in the presence of a catalyst, the catalyst contains or substantially consists of carbonyldiimidazole.

[0058] This disclosure further relates to the use of an ion-conducting polymer binder according to the first embodiment in a slurry for manufacturing a cathode according to the second embodiment.

[0059] The embodiments of the invention will be described in more detail below with reference to the attached drawings. The same reference numerals indicate the same features. [Brief explanation of the drawing]

[0060] [Figure 1] This figure shows the 1H nuclear magnetic resonance (1H-NMR) spectrum of the first ion-conducting polymer binder of the present invention. [Figure 2] This figure shows the Fourier transform infrared (FTIR) spectrum of the first ion-conducting polymer binder. [Figure 3]This figure shows the thermogravimetric analysis (TGA) of the first binder. [Figure 4] This figure shows the differential scanning calorimetry (DSC) analysis of the first binder. [Figure 5] This figure shows the linear sweep voltammetry (LSV) analysis of the first binder. [Figure 6] This figure shows the H-NMR spectrum of the second ion-conducting polymer binder of the present invention. [Figure 7] This figure shows the FTIR spectrum of the second binder. [Figure 8] This figure shows the TGA analysis of the second binder. [Figure 9] This figure shows the DSC analysis of the second binder. [Figure 10] This figure shows the LSV analysis of the second binder. [Figure 11] This figure shows the ionic conductivity of the first and second binders as a function of polymer concentration. [Figure 12] This figure shows the ionic conductivity of the first and second binders as a function of lithium ion concentration. [Figure 13] This figure shows the porosity of the two positive electrodes and the reference positive electrode of the present invention. [Figure 14] This figure shows the discharge capacity and Coulomb efficiency of a first battery cell including a positive electrode obtained using the first binder. [Figure 15] This figure shows the voltage as a function of the specific capacity of the first battery cell. [Figure 16] This figure shows the discharge capacity and Coulomb efficiency of a second battery cell containing a positive electrode obtained using a second binder. [Figure 17] This figure shows the voltage as a function of the specific capacity of the second battery cell. [Modes for carrying out the invention]

[0061] The ion-conducting polymer binder is a copolymer comprising repeating units of m according to formula (I) and repeating units of n according to formula (II).

[0062] TIFF2026057506000007.tif33170

[0063] and

[0064] TIFF2026057506000008.tif58170

[0065] R1 is (CH2) x -R3 is H or CN, x is 1 to 20, preferably 2 to 15, more preferably 4 to 10, and R3 is H or CN; R2 and R5 are individually C1~C 10 Alkyl or C2-C 10 It is an alkenil; and M is an alkali metal or alkaline earth metal.

[0066] Advantageously, q is 50 to 5000, preferably 75 to 4500, and more preferably 100 to 4000.

[0067] Advantageously, m is 5 to 4500, preferably 10 to 3600. Advantageously, n is 5 to 4500, preferably 10 to 3600.

[0068] Advantageously, the ion-conducting polymer of the present invention has a molecular weight of 10 to 3000 kDa, preferably 11 to 2500 kDa, more preferably 12 to 2000 kDa, and most preferably 13 to 1800 kDa.

[0069] It is understood that the values ​​of m and n, i.e., the number of repeating units according to equations (I) and (II), depend on the total number of repeating units q and the ratio of m to n, i.e., the ratio of the number of repeating units according to equation (I) to the number of repeating units according to equation (II). For example, if q is 3000 and m:n is 2:1, the copolymer contains 2000 repeating units according to equation (I) and 1000 repeating units according to equation (II). If q is 5000 and m:n is 1:1, the copolymer contains 2500 repeating units according to equation (I) and 2500 repeating units according to equation (II).

[0070] The repeating units according to equation (II) determine the ionic conductivity of the polymer binder, while the repeating units according to equation (I) are involved in the bonding properties, i.e., the adhesive strength. It is understood that by changing the ratio of m to n with respect to a constant total number of repeating units q, the ionic conductivity and adhesive strength of an ionic polymer binder can be altered. This results in a highly versatile polymer binder whose properties can be fine-tuned according to other components of the cathode and the electrolyte intended for use in battery cells.

[0071] R1 can be a straight chain or branched, i.e., (CH2) x The chain can be straight or branched. Favorably, R1, i.e., (CH2) x The chain is a straight chain.

[0072] R2 can be a straight chain or branched. Advantageously, R2 is (CH2) y C1~C according to 10 It is an alkyl group, where y is 1 to 10, preferably 1 to 4, more preferably 1 or 2, i.e., CH2 or (CH2)2.

[0073] R5 can be a straight chain or branched. Advantageously, R2 is (CH2) w C1~C according to 10 It is an alkyl group, where w is 1 to 10, preferably 1 to 4, more preferably 1 or 2, i.e., CH2 or (CH2)2.

[0074] Advantageously, the copolymer is a random copolymer, i.e., a copolymer in which repeating units according to formulas (I) and (II) are randomly distributed. Alternatively, and more advantageously, the copolymer is a block copolymer, i.e., a copolymer comprising one or more "blocks" of repeating units according to formula (I) and one or more "blocks" of repeating units according to formula (II). An example of such a copolymer is formula (VI)

[0075] TIFF2026057506000009.tif71170

[0076] The structure is represented as shown, and the copolymer contains one block of n repeating units according to formula (II) and one block of m repeating units according to formula (I).

[0077] An example of an ion-conducting polymer binder is a block copolymer where x is 6, R3 is CN, R2 is (CH2)2, and R5 is (CH2)2, and in particular M is Li.

[0078] TIFF2026057506000010.tif67170

[0079] That is the case.

[0080] A second particularly preferred example of an ion-conducting polymer binder is a binder in which x is 10, R3 is H, R2 is (CH2)2, and R5 is (CH2)2, and in particular M is Li.

[0081] TIFF2026057506000011.tif71170

[0082] That is the case.

[0083] When x is 6, R3 is CN, and R2 is (CH2)2, the first and second intermediate polymers are favorably derived from formulas (VII) and (VIII), respectively.

[0084] TIFF2026057506000012.tif52170

[0085] and

[0086] TIFF2026057506000013.tif58170

[0087] It has a structure that conforms to [the following].

[0088] For example, if x is 10, R3 is H, and R2 is (CH2)2, the first and second intermediate polymers are favorably given by formulas (IX) and (X), respectively.

[0089] TIFF2026057506000014.tif52170

[0090] and

[0091] TIFF2026057506000015.tif58170

[0092] It has a structure that conforms to [the following].

[0093] Advantageously, the ion-conducting polymer binder of the present invention has high heat resistance, meaning it can withstand temperatures of at least 250°C, preferably at least 300°C, and more preferably at least 350°C, as measured by thermogravimetric analysis (TGA) at 10°C / min under an argon flow rate of 60 mL / min. Advantageously, the heat resistance of the ion-conducting polymer binder does not change significantly even if the m-to-n ratio of the polymer changes.

[0094] Advantageously, the glass transition temperature of an ion-conducting polymer binder is determined by the number of repeating units in equations (I) and (II), more specifically by the ratio of m to n of the repeating units. Advantageously, the glass transition temperature is 30–175°C, preferably 50–150°C, more preferably 80–120°C, for example 90–110°C, and this temperature is measured by performing two cycles of differential scanning calorimetry (DSC) in an argon atmosphere from -80°C to over 200°C at a heating / cooling rate of 10°C / min, ensuring a reliable and reproducible glass transition temperature value by adopting the results of the second cycle so that the thermal history of the polymer is reliably erased. It is understood that the precise glass transition temperature of an ion-conducting polymer binder depends on the ratio of m to n.

[0095] Advantageously, the ion-conducting polymer binder exhibits a linear sweep voltammetry (LSV) analysis of 1 mV s in propylene carbonate at room temperature. -1 When measured, it exhibits high oxidation stability of at least 2.5V, preferably at least 3V, more preferably at least 4V, for example, at least 4.5V.

[0096] The positive electrode according to the present invention comprises, or consists of, an active compound and a conductive material in addition to the ion-conducting polymer binder of the present invention.

[0097] The active material can be any cathode active material well known in the art. The cathode is understood to contain two or more active materials. A non-limiting example of a suitable active material is LiNi 0.8 Mn 0.1 Co 0.1 O2 (NMC811) and LiNi 0.6 Mn 0.2 Co 0.2 Lithium nickel cobalt manganese oxide (NMC), such as O2 (NMC622), LiFePO4, LiMn x Fe 1-x PO4(LMFP), LiMn 1.5 Ni 0.5 There are O(LMNO) and V2O5.

[0098] The conductive compound may be any conductive compound well known in the art. The positive electrode is understood to comprise two or more conductive compounds. Advantageously, the conductive compound may contain carbon or consist substantially of carbon. Non-limiting examples of suitable conductive materials include carbon-containing compounds such as carbon black (e.g., C-65), carbon nanotubes (CNTs), graphene, and vapor-grown carbon fibers (VGCF).

[0099] Advantageously, the positive electrode includes a positive electrode current collector. The positive electrode current collector may be any positive electrode current collector known in the art, such as aluminum foil, which may optionally include a carbon-containing coating layer. If the positive electrode includes a positive electrode current collector, the positive electrode may preferably include a layer comprising an active material, a conductive compound, and the aforementioned binder, the layer being in contact with the positive electrode current collector, and preferably adhering to or attached to the positive electrode current collector.

[0100] A non-limiting example of the positive electrode of the present invention is a positive electrode comprising a positive electrode current collector and a layer comprising 85-95% by weight of NMC, 2-10% of a carbon black-containing conductive compound, and 2-10% by weight of the ion-conducting polymer binder of the present invention, relative to the total weight of the layer. Advantageously, the layer consists of NMC, a carbon black-containing conductive compound, and the ion-conducting binder of the present invention, i.e., the sum of these by weight percentages in the layer is 100%.

[0101] A more non-limiting example of the positive electrode of the present invention is a positive electrode comprising a positive electrode current collector and a layer comprising 75-85% by weight of LiFePO4, 5-15% of a carbon black-containing conductive compound, and 5-15% by weight of the ion-conducting polymer binder of the present invention, relative to the total weight of the layer. Advantageously, the layer consists of LiFePO4, a carbon black-containing conductive compound, and the ion-conducting binder of the present invention, i.e., the sum of these by weight percentages in the layer is 100%.

[0102] The positive electrode according to the present invention can be manufactured by methods well known in the art. A preferred method includes preparing a slurry containing the ion-conductive polymer binder, active material, and the conductive compound described above in a solvent, and tape-casting the slurry onto a positive electrode current collector.

[0103] Advantageously, the slurry contains 25-75% by weight, preferably 30-70% by weight, more preferably 35-65% by weight, and most preferably 40-60% by weight, for example, 45-55% by weight, of the total weight of the slurry.

[0104] Advantageously, the solid content of the slurry comprises 75-95% by weight of active material, 1-10% by weight of conductive compound, and 1-10% by weight of ion-conductive polymer binder.

[0105] Advantageously, the solvent is selected from the group consisting of water, N-methyl-2-pyrrolidone (NMP), acetonitrile, methyltetrahydrofuran, cyclohexanone, DMF, and propylene carbonate.

[0106] Advantageously, the positive electrode has an adhesive strength to the positive electrode current collector that, as measured according to the ISO-8510-1 standard, is at least 50 N / m, preferably at least 55 N / m, more preferably at least 60 N / m, for example, at least 75 N / m, or at least 80 N / m. [Examples]

[0107] HO-(CH2)6-NH2 was reacted with di-tert-butyl dicarbonate in the presence of tetrahydrofuran at room temperature for 15 hours. After removing the solvent, the reaction product was placed in diethyl ether and washed with acetic acid and aqueous sodium bicarbonate. The solvent was removed under vacuum. The resulting reaction product was then reacted with methanesulfonyl chloride / triethylamine in the presence of dichloromethane (DCM) at room temperature for 3 hours. The mixture was washed with aqueous sodium bicarbonate. After removing the dichloromethane, the resulting product was reacted with KCN at 80°C for 18 hours in the presence of DCM as the solvent. The reaction product was then placed in an aqueous ethyl acetate mixture and washed with water and brine. The organic matter was recovered and the solvent was removed under vacuum. The resulting reaction product was then reacted with HCl in 1,4-dioxane at a temperature between 0°C and room temperature for 5 hours. The reaction was quenched with sodium bicarbonate, the product was extracted with dichloromethane, and treated with sodium hydroxide to obtain H2N-(CH2)6-CN ("amino derivative").

[0108] Next, the amino derivative was subjected to the repeating units of q in the presence of DMF at room temperature for 2 hours.

[0109] TIFF2026057506000016.tif23170

[0110] The polymer containing was reacted with F3CO2SN for 2 hours at room temperature in the presence of DMF. - O2S(CH2)2NH2Li + The reaction was carried out. Next, the resulting reaction product was first heated at 50°C for 4 hours in the presence of DMF, and then further heated at 170°C for 16 hours in the presence of DMF.

[0111] Figures 1 and 2 show the 1H nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectra of the obtained ion-conducting polymer binders, respectively.

[0112] Figure 3 shows the TGA analysis of the binder, demonstrating high heat resistance exceeding 300°C. Figure 4 shows the DSC analysis of the binder, indicating a glass transition temperature of 104°C. Figure 5 shows the linear sweep voltammetry (LSV) analysis of the polymer binder, demonstrating high oxidation stability exceeding 4V. [Examples]

[0113] H2N-(CH2)9-CH3 as an amino derivative was subjected to q repeating units in the presence of DMF at room temperature for 2 hours.

[0114] TIFF2026057506000017.tif23170

[0115] The polymer containing was reacted with F3CO2SN for 2 hours at room temperature in the presence of DMF. - O2S(CH2)2NH2Li + The reaction was carried out. Next, the resulting reaction product was first heated at 50°C for 4 hours in the presence of DMF, and then further heated at 170°C for 16 hours in the presence of DMF.

[0116] Figures 6 and 7 show the H-NMR and FTIR spectra of the obtained ion-conducting polymer binders, respectively.

[0117] Figure 8 shows the TGA analysis of the binder, demonstrating high heat resistance exceeding 300°C. Figure 9 shows the DSC analysis of the binder, indicating a glass transition temperature of 91°C. Figure 10 shows the LSV analysis of the polymer binder, demonstrating high oxidation stability of at least 5V.

[0118] The ionic conductivity of the polymer binders in Examples 1 and 2 was measured at room temperature after dispersing the polymer binder in propylene carbonate. Figures 11 and 12 show the ionic conductivity as a function of polymer concentration and lithium ion concentration, respectively. -3 ~5×10 -5 S·cm-1 It can be seen that excellent values ​​were obtained within this range. [Examples]

[0119] Next, cathodes were fabricated using the ion-conducting polymer binders of Examples 1 and 2. A first slurry was prepared using the binder of Example 1, which had a solid content of 46-48% by weight, and a second slurry was prepared using the binder of Example 2, which also had a solid content of 46-48% by weight. NMP was used as the solvent for both slurries. The solid content of each slurry contained 90% by weight of NMC622 as the active material, 5% by weight of carbon black (C-65) as the conductive compound, and 5% by weight of each ion-conducting polymer binder. As a result, the loading of the active material in the slurry was 3-4 mAh cm⁻¹. -2 That's what happened.

[0120] Next, the slurry was tape-cast onto carbon-coated aluminum foil, which served as the positive electrode current collector, using the doctor blade method (doctor blade coating technology), thereby obtaining the positive electrode. In other words, the positive electrode consisted of a positive electrode current collector and layers made of NMC622, C-65, and an ion-conducting polymer binder.

[0121] The reference cathode was also prepared by tape casting a slurry with similar solid content and loading using the doctor blade method. The solid content consisted of 90% by weight of NMC622 as the active material, 5% by weight of carbon black (C-65) as the conductive compound, and 5% by weight of polyvinylidene fluoride (PVdF) as the binder.

[0122] The porosity of all three positive electrodes, more specifically the porosity of the layer on the current collector, was measured by dividing the density of the positive electrode by the theoretical density. Figure 13 shows that the porosity of the positive electrode of the present invention is higher than that of the reference positive electrode.

[0123] Peel strength, expressed as adhesive strength and measured according to ISO-8510-1, was also measured. The adhesive strength of the positive electrode obtained using the binder of Example 1 was 60 N / m, and the adhesive strength of the positive electrode obtained using the binder of Example 2 was 80 N / m, while the adhesive strength of the reference positive electrode containing PVdF was only 41 N / m. In other words, the ion-conducting positive electrode of the present invention exhibits significantly superior adhesive strength compared to the reference positive electrode. [Examples]

[0124] Three coin cells were assembled using the positive electrode of the present invention in Example 3. The negative electrode was a lithium metal negative electrode, and the electrolyte was a liquid electrolyte containing 1 M LiPF6 in a solvent mixture containing ethylene carbonate and dimethyl carbonate in a 1:1 volume ratio.

[0125] Two of the coin cells were tested at least 30 times in a climate chamber at 25°C, i.e., an oven that can be precisely controlled and maintained at a pre-set temperature (25°C in this case), at various current rates, namely C / 20, C / 10, C / 5, C / 2, and 1C, and no problems were observed.

[0126] Figure 14 shows the discharge capacity and Coulomb efficiency of two coin cells containing a positive electrode obtained using the binder of Example 1. Despite the harsh test conditions, it can be seen that a very high Coulomb efficiency of nearly 100% was obtained, along with excellent rate characteristics and high discharge capacity. This indicates that the ion-conductive polymer binder provides excellent adhesion and enables the cell's cycle characteristics. Furthermore, the results for both coin cells are very similar, indicating that the behavior of the positive electrode and, consequently, the ion-conductive polymer binder of the present invention is very stable and reproducible. Figure 15 shows the voltage as a function of specific capacity. Excellent capacity exceeding 120 mAh / g was recorded at a 1C rate. Polarization was confirmed to begin at a C / 2 rate, but despite this polarization, high discharge capacity was maintained.

[0127] Figure 16 shows the discharge capacity and Coulomb efficiency of three coin cells, including the positive electrode obtained using the binder of Example 1. Despite the harsh test conditions, it can be seen that excellent rate characteristics and high discharge capacity were obtained, in addition to a very high Coulomb efficiency of nearly 100%. This indicates that the ion-conducting polymer binder provides excellent adhesion and enables the cell's cycle characteristics. Furthermore, the results for all coin cells are very similar, indicating that the behavior of the positive electrode and, consequently, the ion-conducting polymer binder of the present invention is very stable. Figure 17 shows the voltage as a function of specific capacity. Excellent capacities exceeding 120 mAh / g were recorded at a 1C rate. Polarization was confirmed to begin at a C / 2 rate, but despite this polarization, high discharge capacity was maintained.

Claims

1. Repeating units of m according to equation (I), and repeating units of n according to equation (II), and A positive electrode ion-conducting polymer binder containing, R １ (CH ２ ) ｘ -R ３ And x is 1 to 20, and R ３ is H or CN; R ２ and R ５ are each C １ to C １０ alkyl or C ２ to C １０ alkenyl; M is an alkali metal or alkaline earth metal; The ratio of m to n (m / n) is 25:1 to 1:25; and m + n is q, and q is between 50 and 5000. Ion-conducting polymer binder.

2. x is 6, R ３ CN, R ２ (CH ２ ) ２ , and R ５ (CH ２ ) ２ The ion-conducting polymer binder according to claim 1.

3. x is 10, R ３ H and R ２ (CH ２ ) ２ , and R ５ (CH ２ ) ２ The ion-conducting polymer binder according to claim 1.

4. The ion-conducting polymer binder according to claim 1, wherein M is Li, Na, or Mg, preferably Li.

5. A positive electrode comprising the ion-conducting polymer binder described in claim 1.

6. The positive electrode according to claim 5, comprising 75 to 95% by weight of an active material, 1 to 15% by weight of a conductive compound, and 1 to 15% by weight of the ion-conducting polymer binder, based on the total weight of the positive electrode.

7. The positive electrode according to claim 6, wherein the porosity is at least 20%.

8. The active material is lithium nickel cobalt manganese oxide (NMC), preferably NMC811 or NMC622, LiFePO ４ , and V ２ O ５ The positive electrode according to claim 6, comprising one or more of the above.

9. The positive electrode according to claim 5, comprising 85 to 95% by weight of NMC, 2 to 10% of a carbon black-containing conductive compound, and 2 to 10% by weight of the ion-conducting polymer binder according to claim 1, based on the total weight of the positive electrode.

10. 75 to 85% by weight of LiFePO4 relative to the total weight of the positive electrode ４ The positive electrode according to claim 5, comprising 5 to 15% of a carbon black-containing conductive compound and 5 to 15% by weight of the ion-conductive polymer binder according to claim 1.

11. A method for producing an ion-conducting polymer binder according to claim 1, - H ２ N-R １ The amino derivatives according to formula (III) A step of reacting with a polymer containing repeating units of q according to R １ (CH ２ ) ｘ -R ３ And x is 1 to 20, and R ３ is H or CN; R ２ is C １ ~C １０ Alkyl or C ２ ~C １０ It is an alkenil; and q is between 50 and 5000. Temperature T of 15-50°C in the presence of dimethylformamide (DMF) １ This is a reaction step that is carried out to form a first intermediate polymer. - The first intermediate polymer is subjected to a temperature T of 15 to 50°C in the presence of DMF. ２ So, F ３ CO ２ SN － O ２ S-R ５ -NH ２ M ＋ It will react with R ５ is C １ ~C １０ Alkyl or C ２ ~C １０ The step of forming a second intermediate polymer, wherein M is an alkenyl and M is an alkali metal or alkaline earth metal, - A step of closing the imide ring of the second intermediate polymer, thereby forming the ion-conducting polymer binder, The ring closure of the imide ring is performed by the second intermediate polymer in the presence of DMF at a temperature of 30 to 80°C T ３ Heat to T ３ Temperature T from 100 to 250°C ４ This is done by doing so, or in the presence of a catalyst. ２ Steps to be performed A method that includes this.

12. The first intermediate polymer comprises n repeating units according to formula (III) and formula (IV) It includes a repeating unit of m according to the formula, where m + n is equal to q. The method according to claim 11.

13. The second intermediate polymer is a repeating unit of m according to formula (IV), and formula (V) It contains a repeating unit of n according to the formula, where m + n is equal to q. The method according to claim 12.

14. The method according to claim 11, wherein M is Li, Na, or Mg.

15. The aforementioned imide ring is T in the presence of a catalyst. ２ The method according to claim 11, wherein the ring is closed and the catalyst comprises carbonyldiimidazole.

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